1. Field of the Invention
The invention relates to the field of low wattage power units for use with small appliances, toys, or as a battery charger. In particular, the invention relates to a universal power module which by means of different connection cables can provide AC or DC power to a variety of small appliances.
2. The Prior Art
U.S. Pat. No. 3,217,227 discloses a battery charging box 10, operative to receive different sizes of battery by means of a base having various sizes of radii 84, 86, 88. The charging rates are established by use of lightbulbs 14, 20 having differing resistance characteristics. An adjustable contact 96 is used to compensate for differing battery lengths.
U.S. Pat. No. 3,900,783 discloses use of a selectively wired cable plug and socket 19, 23 to complete the connection between the rectified AC on lines 16, 47 and the battery 25.
U.S. Pat. No. 4,009,429 discloses a source of rectified AC 11, selectively connected to a battery block 13 through terminals 19, 21 and 23 on the power module 11 and terminals 25, 27, 29 on the battery block 13. Each battery block 12 is designed to handle a different size battery. Springs 64 of a conical shape act as electrical contacts and mechanically clamp the battery 44 to be charged into the battery box 13.
U.S. Pat. No. 3,696,283 discloses a battery charger wherein each different size battery has its own charging module 53, 55, 57, 59 or 61 plugged into a power module 51.
U.S. Pat. No. 3,209,230 discloses a multi-battery charging box 11. The support brackets 24, 25, FIG. 4, will accommodate different sizes of batteries. Springs 38, 48, 58 and 66 have a conical shape and in FIGS. 5, 6 are shown disposed so as to be aligned over the centers of the batteries to be rechargeable.
U.S. Pat. No. 3,579,075 discloses a battery box 10 with supports 28, 30 for various size batteries. Spring 26 loads contact structures 24a, 24b which are adjustable to accommodate differing size batteries.
U.S. Pat. No. 2,920,260 a battery charger and power inverter system.
U.S. Pat. No. 3,193,750 discloses a method of automatically altering the charging rates based on the voltage of the battery being charged.
U.S. Pat. No. 4,006,396 discloses adjusting charging rates automatically based on a sensing resistor attached to the sensing of the battery to be charged.
U.S. Pat. No. 2,418,141 discloses an adjustable battery holder with a sliding contact 21 which compensates for different length batteries.